Box Compression Tester: Formula, Test Procedure, and Applications

Packaging boxes usually come under great stress while storing and transporting them, and this might cause them to collapse. This negatively impacts product safety and causes loss of money. Their structural integrity and durability are of prime importance to preserve product integrity along the supply chain.

A box compression tester is a solution to this problem that serves as a reliable solution for measuring the compressive strength of packaging boxes under conditions of simulated loads. Such a test ensures that their packaging maintains industry standards.

What is Box Compression Tester?

The Box Compression Test machine is a specialized equipment used to determine the load-carrying capacity and structural strength of packaging material. This tester is mainly employed to test corrugated boxes or cardboard and measure the maximum load a box can sustain without losing its integrity or sustaining structural failure. The BCT tester works by applying equal pressure on the box to measure its structural resistance.

The box compression tester provides quick and precise measurement of the compression strength of the box. It is an important assessment of product quality and its load-bearing capacity during storage and transmission.

How Box Compression Tester Works?

A box compression tester works by applying a controlled, escalating compressive force to a box and measures how it responds. It reproduces actual stacking and handling conditions to assess the ability of a box to resist pressure and protect products from damage.

The following are the major components of the box compression tester that work together for the best results:

• Compression Plates – Two flat metal plates; the top plate travels to press down.
• Load Cell – Monitors the amount of force on the box.
• Motor/Drive System – Drives the top plate at a predetermined rate.
• Control Unit or Software – For setup, running tests, and displaying results.
• Safety Features – To stop the mechanism in case of emergency, overload protection, etc.

Box Compression Test Formula

The empirical BCT formula is commonly employed to calculate the compression strength of a corrugated box without actually testing it:

BCT = 5.87 × ECT × √(U × D)

Where:

BCT = Box Compression Strength (in pounds)

ECT = Edge Crush Test value (in pounds per inch, lb/in)

U = Box perimeter (the sum of all four sides of the base, in inches)

D = Box depth (height, in inches)

Box Compression Test Strength (BCT) calculator

The box compression test is performed using the BCT calculator, which measures box thickness, perimeter, and other dimensions of a corrugated box or other products. The result help in predicting the maximum load a corrugated box can sustain in various real-world scenarios.

Example of Box Compression Test Calculation:

ECT = 44 lb/in

Box size = 18 in × 12 in × 14 in

Then:

Perimeter = 2 × (18 + 12) = 60 in

Depth = 14 in

BCT = 5.87 × 44 × √(60 × 14)

BCT ≈ 5.87 × 44 × √840 ≈ 5.87 × 44 × 28.98 ≈ 7500 lbs

Note: This equation is acceptable for single-wall boxes. For double- or triple-wall boxes, direct testing or correction factors are advisable.

Box Compression Test Procedure 

A box compression test method is carried out by applying an incrementally increasing compressive load to a box until it crushes or collapses, and recording the amount of force. The test helps identify a box's stacking strength and checks that it will be able to support the loads that it may incur when being shipped and stored.

Step 1: Condition the Sample

• Select a standard-sized corrugated box sample.

• Make sure the box is empty, in good shape, and free from previous damage.

• Condition the sample in a controlled environment (temperature/humidity) if necessary, according to standards.

Step 2: Calibrate the Equipment

• Switch on the equipment and make sure it's calibrated.

• Zero the load on the load cell.

Step 3: Position the Box

• Position the box in the middle of the base plate.

• Position it correctly so that the load will be distributed evenly.

Step 4: Determine Test Parameters

• Establish test parameters like:

• Compression speed (usually 12.5 mm/min or according to ASTM/DIN specifications)

• Maximum load capacity or end condition (stop on collapse or after a load limit)

Step 5: Begin the Test

• Begin the test by using the control panel.

• The top plate descends, causing a compressive load on the box.

Step 6: Observe the Test

• Watch the load vs. displacement chart in real-time (if applicable).

• Observe for collapse or deformation of the box.

Step 7: Document Results

• The machine automatically stops when:

• The box is collapsed

• A predetermined load is attained

• The prescribed displacement is reached

• Document the compressive strength maximum in kN or kgf.

Step 8: Interpret and Report

• Compare the result against packaging standards (e.g., ASTM D642, ISO 12048).

• Utilize data for packaging design, material selection, or quality control.

Applications of Box Compression Tester

A Box Compression Tester is specifically intended to test the compressive strength and load-carrying capacity of packaging material. It ensures they are capable of withstanding the requirements of storage and shipment. 

Below are some significant applications that a Box Compression Tester finds use in different industries:

• Packaging Industry

The packaging business is concerned with the creation and manufacturing of materials that shield products when handling, storing, and shipping them. Some of its components are corrugated boxes, cartons, and other containers. Packaging strength is essential, and the Box Compression Tester has a vital function in testing a package's capacity to withstand compressive stresses in actual conditions.

• Food and Beverage Industry

For the food and beverage sector, box compression testers are applied to assess the integrity of corrugated packaging that safeguards fragile and durable products. Conditioning boxes to withstand transport and storage pressure assists in maintaining product integrity while providing economical delivery across the supply chain.

• Pharmaceuticals

In the pharmaceutical sector, box compression testers play an important role in testing the strength of corrugated cartons for shipping medicines and medical equipment. Packaging integrity ensures damage-free storage and transport, and ensures product safety and regulatory compliance in the handling of valuable pharmaceutical products.

• Shipping and Logistics

In the logistics and shipping business, the box compression tester is vital in assessing the durability of packaging handled during shipping. It ensures boxes withstand stacking, vibration, and handling forces. It avoids product damage, optimizes packaging efficiency, and maintains the supply chain's customer satisfaction. 

• Warehouse Storage

In the storage and warehouse sector, box compression testers guarantee that packaging can withstand vertical storage loads. They prevent box collapse upon long storage and ensure product integrity. It also maximizes the use of space by ensuring that packages can satisfy the strength requirements that are critical for safe storage.

Conclusion 

The box compression tester is critical for assessing packaging structural strength. It uses standardized processes and equations to verify that boxes can withstand stacking and transit loads. The compression test is used for quality control, packaging, and logistics, making it a key to product safety and supply chain efficiency.

Presto Instruments is a leading box compression tester manufacturer in Sri Lanka, committed to global quality standards. Our equipment is designed to improve product reliability, reduce defects, and ensure consistent performance. Trusted by industries worldwide, we offer reliable and customized solutions to meet your testing needs. Contact us today.